Boiler, more particularly oil burning sectional boiler



F. IRSCHIK July 5, 1938.

BOILER, MORE PARTICULARLY GIL BURNING SECTIONAL BOILER Filed May, 22, 1935 UH Q1 no 4 a... H H Ll l-l HHHHHHHH Patented July 5, 1938 UNITED STATES PATENT OFFICE Franz Irschik, Purkersdorf, Austria Application May 22, 1935, Serial No. 22,876 In Austria May 23, 1934 1 Claim.

This invention relates to the lay-out of boiler flue passages, more particularly for sectional boilers heated by the combustion of oil fuel, and is characterized essentially by the arrangement that 5 the combustion chamber or fire-box is directly or indirectly connected with the forward end of the ash'chamber beneath the grate, while this latter is connected to the outside flue or Smokestack.

The invention is equally applicable to boilers originally intended for coke and converted for operation by oil combustion and to boilers designed for oil burning but capable of being adapted subsequently to work with coke.

Experience has shown that coke boilers, when converted for oil burning, need to be enlarged to a certain extent if they are in practice to give the same heat output. This is due to the fact that in consequence of the peculiar nature and shape of the oil flame the effective utilization of the aggregate heating surface of the boiler is not uniform, the rearward sections of the boiler, that is to say the sections furthest from the burner and nearest to the flue outlet, being thermically overloaded, while the sections towards the front are but insufficiently utilized. Furthermore, a certain amount of the available direct heating surface is lost through the blocking up of the grate with fireproof material, and in addition a still further loss of heat is incurred by reason of the relatively high waste gas temperature due to the shortness of the paths of escape through the flue passages.

The present invention completely overcomes all these drawbacks at one blow and provides the advantage, in addition to more complete utilization of the liquid fuel used, of enabling existing boilers to be adapted for oil burning without expensive structural alterations and without any detrimental effect on the life of the boiler.

40 In adapting vertical sectional boilers for oil burning, it has hitherto been the usual practice to connect up the horizontal flues, into which the vertical flue passages between the individual sections discharge, directly to the main flue or breeching. The burner flame and the combustion gases thereof are thus blown towards the rear of the boiler where they first rise and then are drawn down the vertical flue passages into the horizontal collecting flues whence they at once escape into the breeching. The result is the above-mentioned unequal utilization of the effective heating surface of the boiler sections, since the rear sections are thermically overloaded while the front part of the boiler is quite inadequately utilized.

In accordance with the present invention, the furnace gases are not taken straight into the breeching from the collecting flues at the side .of the boiler but are drawn to the front from these collecting flues, and also compelled both in 5 the combustion chamber and in the vertical flue passages between the sections to play over the surface of the sections at the front end of the boiler. In the combustion chamber the draught of the boiler thus tends to counteract the blast 10 of the burner, which has a favorable effect both on the shape of the flame and. on the manner and directions in which the furnace gases are drawn off through the flue passages. From the collecting flues at the side of the boiler the furnace 15 gases are conducted, preferably by means of a special reversing or deflecting attachment, into the ash chamber of the boiler, which is normally a dead space in boilers converted for oil burning, where they play over the surface of the waterso cooled grate bars and of the portion of the heating surface of the boiler situated below the grate, after which they pass into the breeching connected to the rear end of the ash chamber.

In spite of the great increase in the aggre- 25 gate length of the distance traveled by the furnace gases in the flue passages of the boiler it is not necessary to take any steps for increasing the strength of the draught, since experience shows that the up-takes dimensioned for coke to burning are amply large enough for oil burning under the conditions provided by the present invention, while if there should happen to be any deficiency of draught, the forced draught set up by the fan blower of the burner is fully capable :35 of making up for this deficiency. It has surpisingly transpired, however, in the course of practical experience with the present invention, that no appreciable diminution of the draught is brought about in spite of the increase in the total lo distance traveled by the furnace gases in the boiler, which is probably due to the fact that with the usual lay-out of the flue passages in boilers converted for oil burning, as a result of the concentration of the bulk of the furnace gases in 45 the vertical flue passages at the rear end of the boiler there tend to be set up choking effects and eddies which do not occur with the lay-out according to the present invention. The result is that any increase in resistance due to the greater 50 distance to he traveled by the furnace gases in the boiler is compensated for by the gain due to the avoidance of any choking and eddy formation in the flue passages.

A form of construction embodying the inven- 55 tion is shown diagrammatically and by way of; examplei in the accompanying drawing, in which::

Figs. 1 and 2 are vertical sections taken in twoi different planes; of a sectional boiler having a flue passage lay-out in accordance with the present invention.

Fig. 3 is a section taken on the line IIIIII of Fig. 2. Y r E? Fig. 4 shows diagrammatically the hitherto usual flue passage lay-out in a sectional boiler converted for oil burning.

Fig. 5 shows diagrammatically the flue passage lay-out according to the present invention.

Fig. 6 is an isometric diagrammatic view illus-' trating the application of a flue reversing or defleeting chest to the front end of the boiler, in accordance with the present invention.

The sectional boiler with vertical flue passages shown Figs. 1 to 3 is of conventional constriction and heated by means of an eil burner denoted by I. The furnace gases rise in the combustion chamber 2, and pass through the vertical flue passages 3, 3' into the two collecting flues 4 and 4 at the side of the boiler. Accord.- ing to the practice normally followed hitherto, these two collecting flues 4 and 4' are connected atthe back'of the boiler at 5 (Figs. 1 and 3) into the breeching 6, so that the furnace gases travel, as indicated in Fig. 4, upwards in the fire-box at the rear end, down through the vertical flue passages at the rear end of the boiler, and then straight out into the breeching 6.

In accordance with the present invention, the connection between the lateral collecting flues 4, 4 and the breeching is cancelled, and instead there is established at the front of the boiler a connection between these flues and the ash chamber 7 of the boiler, and this latter chamber is connected at its rear end into the breeching. Thus, after the usual blocking up the grate, the furnace gases are compelled to take the fol lowing course: starting from the combustion chamber 2, downwards through the vertical flue passages 3, then towards the front (instead of as hitherto towards the rear straight into the breeching through the deflecting attachment or chest 8 in which their direction of flow is deflected through 180, and then through the length of the ash chamber 1 into the breeching 6 (see Fig. 5).

The connection between the lateral collecting flues and the ash chamber is preferably established by means of a chest-like attachment adapted for application to the front end of the boiler and made of metal, fire-brick, slabs of refractory material, or the like. It is also possible to establish this connection within the boiler itself, for instance by providing suitable apertures in the partition 9 between the twochambers, at

the front end. The layer of refractory material covering and blocking up the grate is denoted by I 0., W

The original communication between the collecting flues 4 and thebreeching 6 is either walled up or'obstruc ted by means of a lid I l or the like. It has also proved useful to block this communication by means of movable flaps or dampers so as to provide for short-circuiting the draught; of

.the boiler if desired, for instance in jstarting'up from cold, and to obtain a temporary increase in the strength of the draught. i

Finally, in the deflecting chest 8, inthe vicinity of the connection to the flues l, 4', there are provided throttling flaps H which also serve for the regulation of the draught. The provision of dampers at this point has the advantage over the usual arrangement, that they can be manipulated more easily and without the use of transmission elements. A main damper I3 is alse. provided in the usual manner in the connection to the breeching. The deflecting chest 8 is also provided with cleaning doors M for giving access to the fiue passagesforcleaning, and with a connection 8 for the introduction of a pyrometer.

In accordance with the invention, the deflecting attachment can also be utilized for the preheating of the primary and secondary air for combustion and of the fuel. For this purpose air conduits l5, l6, and the fuel pipe I! are taken through the upper part of the chest 8 as shown in Fig. 6, and may if desired be coiled or provided with ribs to aid the transference of heat. The jacket of this chest can also be so constructed as to admit of water-cooling thereof.

I claim:

A boiler comprising encl members, a breeching connected to one of said end members, sections interposed between said members and containing water-spaces communicating with each other and as a whole enclosing a space, a grate dividing said space into a combustion chamber and an ash chamber, a fireproof layer on said grate, an oil burner in said combustion space, said sections having vertical flue passages communicating with said combustion chamber and having transverse openings forming .a collecting fine on each side of sai-dashchamberand communicating with said' vertical flues but closed at the rear end,

means forming a passage from said collecting flue to the forward portion of said ash chamber and including a reversing chamber at the front end of the boiler, dampers in said reversing chamber regulating the rate of discharge fromthe collecting flues into the reversing chamber and doors on the front of said reversing chamber, and said ash chamber communicating at its rear end with said 'breeching.

' FRANZ IRSCI-IIK. 

